Washlights are used to provide lighting accents generally via indirect lighting (i.e., an area is illuminated primarily by light from the illumination source that is reflected off of another surface). For vehicles in general, and specifically here for aircraft, washlights can be used to create various moods, particularly when colored lighting is used.
Advances in light emitting diode (LED) technology has made them an ideal source of light where low-powered lighting solutions are desirable, which is particularly true in aircraft in which power availability is limited. However, with known systems, a degree of sophistication is lacking with regard to the full range of control that is possible with the use of LEDs and light sources having similar properties.
One problem introduced by the use of LED lighting technology is the light output by different LEDs of the same type and model can vary in intensity given the same input electrical signal. Variances in brand new LEDs are due to variances in manufacturing processes. The output of the LEDs can also vary over operating temperature and with the length of time that the LEDs have been in service (i.e., their age). Thus, a washlight installation that includes multiple LED lighting modules may not have uniform lighting characteristics (e.g., color, color temperature, and brightness) if all the LEDs of each type in the LED lighting modules operate using the same input electrical signal. Likewise, a new LED lighting module that replaces one out of many older LED lighting modules in a washlight installation may also not have lighting characteristics that match the older LED lighting module which is replaced when operating using the same input electrical signal.